Optimizing the thermomechanical and thermal performance of epoxidized natural rubber hybrid nanocomposites using graphene and carbon nanotubes

Hybrid nanocomposites, comprising epoxidized natural rubber (ENR) filled with graphene (GP) and carbon nanotubes (CNTs), were prepared via the melt mixing technique. TEM imaging confirmed the development of three-dimensional filler networks, facilitated by the π-π interaction between sp²-hybridized carbon atoms in graphene and carbon nanotubes, alongside Van der Waals forces. Moreover, a notable interaction between polar functional groups on the nanofiller surfaces and the ENR molecules emerged as a significant factor in enhancing properties. This was evidenced by the rise in bound rubber content with increasing CNT loading, amplifying reinforcing efficiency through the establishment of bridge links among rubber chains and filler networks. Temperature scanning stress relaxation (TSSR) results unveiled escalating relaxation forces, moduli, and crosslink density upon nanofiller incorporation and with increasing CNT loading. DMA results indicate elevated storage modulus and glass transition temperature (T_g), coupled with reduced coefficient of reinforcement (C-factor), indicative of an increased degree of reinforcement.